Gigantopelta chessoia

Gigantopelta chessoia is a species of deep sea snail from hydrothermal vents, a marine gastropod mollusk in the family Peltospiridae.

However, the taxonomy of the Gastropoda (Bouchet & Rocroi, 2005) does not use the name Peltospiroidea (in that system, Peltospiridae is placed within the superfamily Neomphaloidea).

[3] The respiratory system consist of single left bipectinate ctenidium (gill).

[5] This indicates that carbon fixation in Gigantopelta chessoia can occur via Calvin-Benson-Bassham cycle by endosymbiotic Gammaproteobacteria.

[5] The occurrence of endosymbiont bacteria in the oesophageal gland was confirmed by transmission electron microscopy in 2017.

[3] The oesophageal gland is fused and enlarged to fill the entire ventral side of mantle cavity.

[3] The reproductive system has fully developed gonads in juveniles at body size 2.0 mm.

[2] Gigantopelta chessoia may be a mixotroph in juvenile life and shifting to obligate symbiotrophy as an adult.

Location of E2 and E9 sites in the Scotia Sea showing the East Scotia Ridge (ESR) between the Scotia Plate (SCO) and South Sandwich Plate (SAN).
Dorsal view of Gigantopelta chessoia showing a mantle cavity overview. The shell and mantle tissue have been removed. Scale bar is 1 cm.
Cross section of Gigantopelta chessoia showing enlarged oesophageal gland (og).
ct – ctenidium,
si – blood sinus,
pm – pedal muscle.
The scale bar is 1 cm.
This area between hydrothermal vent chimneys on the E9 site at a depth of 2,398 m is occupied by Gigantopelta chessoia . Scale bar is 1 m.